2 files changed, 66 insertions, 0 deletions
diff --git a/lib/puppet/parser/functions/ensure_packages.rb b/lib/puppet/parser/functions/ensure_packages.rb
new file mode 100644
index 0000000..450ea02
--- /dev/null
+++ b/lib/puppet/parser/functions/ensure_packages.rb
@@ -0,0 +1,24 @@
+#
+# ensure_packages.rb
+#
+require 'puppet/parser/functions'
+
+module Puppet::Parser::Functions
+  newfunction(:ensure_packages, :type => :statement, :doc => <<-EOS
+Takes a list of packages and only installs them if they don't already exist.
+    EOS
+  ) do |arguments|
+
+    raise(Puppet::ParseError, "ensure_packages(): Wrong number of arguments " +
+      "given (#{arguments.size} for 1)") if arguments.size != 1
+    raise(Puppet::ParseError, "ensure_packages(): Requires array " +
+      "given (#{arguments[0].class})") if !arguments[0].kind_of?(Array)
+
+    Puppet::Parser::Functions.function(:ensure_resource)
+    arguments[0].each { |package_name|
+      function_ensure_resource(['package', package_name, {'ensure' => 'present' } ])
+    }
+  end
+end
+
+# vim: set ts=2 sw=2 et :
diff --git a/spec/functions/ensure_packages_spec.rb b/spec/functions/ensure_packages_spec.rb
new file mode 100644
index 0000000..1c2a328
--- /dev/null
+++ b/spec/functions/ensure_packages_spec.rb
@@ -0,0 +1,42 @@
+#! /usr/bin/env ruby
+
+require 'spec_helper'
+require 'rspec-puppet'
+
+describe 'ensure_packages' do
+  let(:scope) { PuppetlabsSpec::PuppetInternals.scope }
+
+  describe 'argument handling' do
+    it 'fails with no arguments' do
+      should run.with_params().and_raise_error(Puppet::ParseError)
+    end
+    it 'requires an array' do
+      lambda { scope.function_ensure_packages([['foo']]) }.should_not raise_error
+    end
+    it 'fails when given a string' do
+      should run.with_params('foo').and_raise_error(Puppet::ParseError)
+    end
+  end
+
+  context 'given a catalog containing Package[puppet]{ensure => absent}' do
+    let :pre_condition do
+      'package { puppet: ensure => absent }'
+    end
+
+    # NOTE: should run.with_params has the side effect of making the compiler
+    # available to the test harness.
+    it 'has no effect on Package[puppet]' do
+      should run.with_params(['puppet'])
+      rsrc = compiler.catalog.resource('Package[puppet]')
+      rsrc.to_hash.should == {:ensure => "absent"}
+    end
+  end
+
+  context 'given a clean catalog' do
+    it 'declares package resources with ensure => present' do
+      should run.with_params(['facter'])
+      rsrc = compiler.catalog.resource('Package[facter]')
+      rsrc.to_hash.should == {:name => "facter", :ensure => "present"}
+    end
+  end
+end